Aspergillus oryzae cells were entrapped within agarose beads. These entrapped cells, having α-galactosidase activity of 0.72 IU/ml, were used for hydrolyzing flatulence-causing galacto-oligosaccharides present in soymilk. The total of 52% raffinose, 70% stachyose, and 66.3% total oligosaccharides of soymilk was observed to be hydrolyzed in 8 h at 50°C by these immobilized cells.